I have a commercial lease on a resort. The lease includes a statement that it can be extended an additional 5 years "by either party". I made many renovations and invested a lot of money relying on that term. planning to extend.

Now when I informed the landlord that I plan to extend he stated that he interprets "either party" to mean "both parties" and that he chose not to extend it. I told him that I thought the meaning of "either" was very clear. Keep in mind that the option is for either party to extend the lease, it does not say either party may choose not to extend the lease.

My friend played the devils advocate and says that the judge could find in his favor since the landlord could not really extend the lease unilaterally if I wanted to end it, so the "either party" term is ambiguous.

I'd like to know if there is any jurisprudence regarding the meaning of the right of "either party" to extend the lease, or what's your opinion.